2025 - A new coronavirus, COVID-25, spreads across the globe killing hundreds of thousands before disappearing. They thought the worst was over... until four years later, when the more virulent COVID-29 strikes, wiping out 80% of the world's population. The government rapidly constructs an underground complex - the bunker - to safeguard 50 specially selected infants and young children to be mankind's last hope. When the bunker's last adult dies 12 years later, the quarantined teenagers must form their own society within the bunker or venture out into the post-plague world.